Aidou's cousin and another one of "Kaname-sama's right hand." His carefree attitude gets both him and Aido in trouble at times. His nickname is "Wild," despite the fact he is actually mellower than Aido. He tends to get blamed for the actions of other vampires, especially Aido, despite not being involved and ends up getting punished as a result. In a bonus story at the end of Volume 2 ("I Must've Been Born Under the "Victim of Circumstances" Star...") he also refers to Kaname as their "gang leader." He is incredibly perceptive and is frequently sensitive to others' feelings, most particularly with Aido and Ruka's. Also seems that he has feelings for Ruka and likes her.
Plot Summary of Vampire Knight
Cross Academy is different from other schools. It has a Day Class and a Night Class, with different uniforms and no interaction between these two classes. Secretly, students of the Night Class are all vampires, led by Kuran Kaname, a noble vampire who 10 years prior saved Cross Yuki from the attack of a stray vampire. Now a Guardian of the Night Class vampires, Yuki works along with fellow classmate Kiriyuu Zero, a young man with a hatred for vampires deeper than anything she could imagine. Together, they protect Kaname and the Night Class vampires from having their identities revealed, as well as protect Day Class students from any vampire attacks that occur due to a vampire's natural thirst for blood. Based on the manga by Hino Matsuri.